Trayvon Martin was just footsteps from his home when he was killed by self-styled neighborhood watchman George Zimmerman.

ATLANTA -- Even in a hoodie, 17-year-old Trayvon Martin could not hide his baby face.

At 140 pounds, few believe the unarmed teen could pose much of a physical threat to the much larger 28-year-old self-styled neighborhood watchman who fatally shot the teen in February. George Zimmerman told police it was self-defense. He has not been charged with a crime, but federal investigators are now looking into the shooting.

"It just hurts -- it really hurts," said Sarah Alexander, a Gwinnett County mother. "When I first heard this story, my heart went out to the family, of course. And I cried because it really hit home."

That's why Alexander drove an hour out of her way to the Paradise Seafood restaurant in South Fulton County. It was one of several locations selling tickets to the Trayvon Martin rally Thursday in Florida. She bought three at $75 apiece.

Alexander will join hundreds, perhaps thousands, from all over the country at Fort Mellon Park in Sanford, Fla. for the event organized by Rev. Al Sharpton, who has called the Martin shooting the Emmett Till murder of this era.

"You have to raise your kids, and you have to tell them, and repeat it so many times, that they are treated differently because of their color," Alexander said. "And that they must act this way when they're in public, when they are in other neighborhoods that are not their own, because you just never know. You just never know if they're going to come back safe or not."

Alexander is taking her 15-year-old son Nick and a nephew on the trip because she believes the rally is as much about them as it is Trayvon Martin, not to mention the chronic, sometimes deadly problem of profiling.

"I would say [I'm] scared, but I can't really say that," Nick said. "But to be thankful for every day that we have. You really just have to mindful of how you speak, how you act, your mannerisms and different things like that. I mean, it is unfair pretty much, but at the same time I feel that it gives us a way to shine brighter than the other people who are living also."

The buses left Atlanta from First Iconium Baptist Church Thursday morning and will arrive in Florida later in the afternoon.